Abnormal behaviour such as a stereotypic movement is very much a concern
when it occurs in relation to animals held in captivity. From a behavioural
standpoint, the behavioural and spatial requirements of nondomestic animals
in captivity greatly depends on the species. For example, the behavioural
requirements of many species appear relatively simple when compared
with
the requirements of a highly specialized carnivorous species such a large
cat. It is often in predators or primates that one observes abnormal
behaviours such as stereotypic movements that are uncommon or otherwise
different than normally occurring by the species in its natural environment.

How do you identify a stereotypic movement?

First it may be useful for the zookeeper or the veterinarian to identify
the abnormal behaviour (the stereotypic movement) as one that occurs by
the nondomestic animal in the captive and not in the species' natural
habitat.
For example, pacing at the fence of an enclosure is a behaviour that has
not been observed in the natural habitat due to the lack of enforced boundaries
in their wild environment. A stereotypic movement can be further categorized
as either one that has no obvious function and is a movement
repeated regularly or as a repeated movement that is an exaggerated form
of a purposeful
behaviour. An example of the first type of stereotypic behaviour is the
figure eight or circular pacing often observed by captive bears. Compulsive
scent marking reportedly observed in marten species, although initially
part of the animal's normal repertoire, can be identified as example of
the latter type of stereotypic movement.

Two basic forms of stereotypic
movements found in the zoo environment are pacing and stationary. Pacing
occurs when the animal moves repeatedly back and forth in a straight line
or perhaps moves in a circular or figure eight pattern in its enclosure.
The straight line pacing is most often observed at the boundary of an enclosure.
The most common stationary movements are repeated nonlocomotive acts such
as rocking, head tossing or weaving.

What is the cause of the stereotypic movements?

One likely cause of these abnormal behaviours is the lack of appropriate
normal stimuli which contributes to boredom and the lack of exercise
(inactivity).
It has been suggested that stereotypic movements may also develop as escape
attempts that cannot be carried out completely because of the inadequate
space in their environment. As well, the proximity to other animals and
to the public may play roles in the initiation of a stereotypic movement.
One example of how a stereotypic movement may evolve is a scenario of the
predatory animal waiting for the zookeeper to deliver its meal. At feeding
time the animal is usually waiting at a specific location in its enclosure.
While the animal is awaiting its meal, the animal may turn around in
restlessness
and follow a fixed path back to its original lookout. This sequence of
events initiates a stereotypical movement that may occur at feeding time
and may eventually occur whenever the animal is hungry. This in an example
of how an insignificant behaviour such as waiting for a meal (predatory
animals for the most part do not wait for a meal to be delivered to them
in the wild) can transform itself into a stereotypic behaviour.

How can the frequency of stereotypic behaviours be
reduced?

When it is presumed that a stereotypic behaviour developed due to a
lack
of novel stimuli then it should be investigated whether the present enclosure
or housing condition is naturalistic so that it closely resembles the habitat
the animal would occupy in the wild. When this is determined, appropriate
steps to introduce the animal to a more complex environment should be carried
out which may alleviate or decrease the stereotypic movement. Another approach
to reduce the stereotypic movement while increasing sensory stimulation
to the animal is through behavioural engineering. This technique utilizes
mechanical devices that provide food as a reward in response to behaviours
that have been selected for through positive reinforcement. One successful
attempt using behavioural engineering to reduce the frequency of pacing
in jaguars was to condition the animals to rear up and strike a paddle
with their forepaw. This behaviour was initiated when the jaguars heard
food entering an automatic feeder mounted in their enclosure. This treatment
ultimately increased the jaguars alertness and significantly decreased
the stereotypic pacing. A third approach to providing novel stimuli in
the enclosure is to install automatic dispensers that release food randomly
throughout the day. For example, the introduction of flying meatballs in
a carnivore enclosure provides an artificial prey which stimulates the
predatory behaviour of an animal such as the serval cat which leaps to
catch its prey. As well, fish released into a polar bear pool can reduce
the stereotypic behaviour observed in captive polar bears (for example
begging, rocking motions) by increasing the activity of the animal. In
summary, the causes of stereotypic movements associated with nondomestic
animals kept in zoos are very complex as briefly illustrated by this text.
Steps can be taken to design habitats and devices the meet both the behavioural
and spatial requirements of the captive animal which may help to alleviate
or reduce the frequency of the stereotypic movements observed.